On 11/02/2020 13:34, Andrew wrote:
On 10/02/2020 15:13, newshound wrote:
Personally I would put in high quality plastic plugs and something
like 5 inch No 12 screws if fixing directly.

Careful. There are some older properties with such thin party walls
you might end up in your neighbours house :-)

Not with a 50 mm standoff though.